The present invention relates to a positioning device for a parts supply tray, and more particularly to such a positioning device suitable for use with an automatic assembly system employing a robot.
Generally, a parts supply tray to be used in an automatic assembly operation employing a robot must maintain a high dimensional accuracy such that an arm of the robot can pick up a part. In the case that a physical distribution tray (a tray for transporting elements between factories) formed of foamed synthetic resin so as foamed styrene resin is used as the parts supply tray, a positioning accuracy of the parts supply tray tends to be influenced by aged deformation of the foamed synthetic resin forming the physical distribution tray. To cover this influence, it is necessary to check a pickup position of the part by using an external sensor such as a TV camera.
Conventionally, the parts contained in the physical distribution tray formed of foamed synthetic resin are not directly supplied to the robot, but they are first transferred to a special parts supply tray having a high dimensional accuracy. Then, the parts supply tray is supplied to a parts supply station for the robot.
In such a conventional method, the parts supply tray to be used with the automatic assembly system requires a high dimensional accuracy such that the arm of the robot can pick up the part from the parts supply tray, causing an increase in manufacturing cost. Further, it is necessary to transfer the parts from the physical distribution tray to the parts supply tray and then rearrange the parts on the parts supply tray by hand. On the other hand, in the case of using the physical distribution tray as the parts supply tray, the positioning accuracy of the physical distribution tray is influenced by aged deformation of the foamed synthetic resin forming the physical distribution tray. To solve this problem, it is necessary to use an external sensor such as a TV camera.